One idea could be a Dragonborn character arriving in the High School DxD world and having to adapt to the unique school and supernatural environment. They might use their dragonborn abilities to stand out in the Rating Games.
Perhaps the Dragonborn could form an unlikely alliance with Issei and his group. The Dragonborn's knowledge of dragons and their own dragon powers could help in battles against stronger foes, like the Devils from other factions. They could also teach the group about different dragon-related magic or skills.
Another plot could involve the Dragonborn being mistaken for a new type of devil or a rare dragon hybrid. This misunderstanding could lead to various comical and also dangerous situations. They might have to prove their true identity while also dealing with the power struggles within the High School DxD universe.
Chapter 187, "Lu Sheng, Unauthorized Mining, Humiliation", is the clearest early answer because it turns Cold Resistance Level's situation into a concrete plot event. Early on, He looked at everyone, a surge of heroic spirit rising in his heart,.... By the end, A series of heavy footsteps suddenly reached his ears..
Chapter 263, "Offering Strategies, An Eldest Brother Like a Father", is the clearest early answer because it turns Xiao Hen's situation into a concrete plot event. It opens with Those stuck without breaking through to the Earth-digging Realm, Xiao... and closes on A sudden knocking interrupted Xiao Hen's thoughts.. The key payoff is that the chapter closes with He glanced at Xiao Ning's belly, indeed sensed a faint pulse of life, immediately smilingly said, "Xia Chuan kept it from me;
Chapter 200, "Xu An, Ten Thousand Urgent, Presenting Treasure", is the clearest early answer because Great Xia gets a payoff that changes the stakes. It opens with After Xu An finished speaking, Li Hun hurriedly set the young man... and closes on And they are gathering other camps to jointly attack Great Xia?. The key payoff is that the chapter closes with ..., which gives Great Xia a stronger narrative position and pushes the battle onward.
Chapter 254, "Alchemy, Special Envoy, and the Partition of Longyou", is the clearest early answer because it turns Jade Bone's situation into a concrete plot event. A useful checkpoint is the way the scene starts with The cultivation method at the Cold Resistance Level is absolutely... and follows through with They've arrived, and quite quickly at that!" After a moment of....
Chapter 261, "The Shock of Peng Bo and Chen Yingyuan, Great Xia Martial Gathering (Part 3)", is the clearest early answer because it turns Qin Feng's situation into a concrete plot event. Early on, Liu Ming might simply think that his grandfather is not too.... By the end, The price of beast meat has been lowered, now 1 contribution point....
Chapter 203, "Shock, Prisoner Rules, and What Constitutes Guilt? (Part 2)", is the clearest early answer because it turns Camp Supply Department's situation into a concrete plot event. It opens with 5,321 people; 124 captives from the Earth-digging Realm, 821 from the... and closes on Then I'm not letting go, wasn't planning to anyway..
Chapter 295, "Deploying the Beehive, Splitting Into Two Groups", is the clearest early answer because it turns Li Xuanling's situation into a concrete plot event. The setup is They came fiercely, but ended up with nothing., but the pressure keeps building through Li Xuanling must be dumbfounded by now..
Chapter 250, "Rescue, Intimidation, and Surprise (Part 2)", is the clearest early answer because it turns Yang Zhong's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Those people in light gold armor have been using solidified fire oil... and follows through with Especially seeing Lu Yang and others who just now seemed proud, now....
Chapter 287, "Cloud Dragon Army's First Battle, Zhou Yuan's Bloody Struggle, Decisive Victory and Unexpected Windfall", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from Once we start circling around, find a chance to leave the group!" The... to Upon hearing, Zhou Yuan's brows furrowed deeply..
Chapter 214, "Meritorious Deed, A Fortunate Accident (Part 3)", is the clearest early answer because it turns Chen Yingba's situation into a concrete plot event. The setup is Among the hunting team's thirty-odd squads, the one with the..., but the pressure keeps building through Xia Hong showed a hint of surprise on his face, looking up at Chen....